title: Comparative proteomics of human male and female tears by two-dimensional electrophoresis.
abstract: The proteomic profile of tear fluid is of fundamental interest in eye research. In this study we optimized the tear sample preparation method for two-dimensional (2D) analysis and determined the protein profile of tear fluid from healthy males and females. To find the most efficient method for tear sample preparation, four widely applied precipitation methods and ultrafiltration were compared. Of these, TCA precipitation & ultrafiltration resulted in efficient sample concentration and desalting. Use of a nonionic wetting agent, Tergitol NP7, in rehydration solution during isoelectric focusing improves protein separation in 2D gel electrophoresis considerably. Using this optimized method, tear protein profile was analyzed from healthy males and females. Of the thirty six tear proteins identified by LC-MS/MS, seven tear proteins were found to be significantly up regulated in the healthy female tear samples when compared to the male tear samples. These results indicate that the tear protein profile differs with respect to the sex. Mostly, the up regulated proteins are involved in the local immune defense; implying that there may be a sex difference in the ability to defend against infection at the anterior segment of the eyes of normal individuals.
authors.affiliation: Dr. G. Venkataswamy Eye Research Institute, Aravind Medical Research Foundation, Aravind Eye Care System, Madurai, India.
authors.forename: Sivagnanam
authors.initials: S
authors.lastname: Ananthi
authors.forename: Ramachandran Sarojini
authors.initials: RS
authors.lastname: Santhosh
authors.forename: Murugesan Valar
authors.initials: MV
authors.lastname: Nila
authors.forename: Namperumalsamy Venkatesh
authors.initials: NV
authors.lastname: Prajna
authors.forename: Prajna
authors.initials: P
authors.lastname: Lalitha
authors.forename: Kuppamuthu
authors.initials: K
authors.lastname: Dharmalingam
mesh_terms: D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D005136:Eye Proteins / Q000032:analysis*; D005233:Fatty Alcohols / Q000494:pharmacology; D005260:Female; D006801:Humans; D007525:Isoelectric Focusing; D008297:Male; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis; D020543:Proteome / Q000032:analysis*; D040901:Proteomics / Q000379:methods; D020539:Sequence Analysis, Protein; D012737:Sex Factors; D053719:Tandem Mass Spectrometry; D013666:Tears / Q000737:chemistry*
chemical_list: D005136:Eye Proteins; D005233:Fatty Alcohols; D010446:Peptide Fragments; D020543:Proteome; C042434:tear proteins; C028095:tergitol 7